Methods quantitating the immunologic components of human milk are greatly needed in order to evaluate these components with respect to potential improvements in infant health. The overall goal of this project is to develop techniques to accurately and rapidly analyze the concentrations and interactions of certain immunologic proteins and non-protein nitrogen components in human milk. Specifically, they will develop a panel of monoclonal antibodies against several of the recognized immunologic factors in human milk and against previously unrecognized or unmeasured subspecies and complexes of the host defense factors. They also will develop of methods for separation, identification, and quantification of low molecular weight sulfur containing compounds in human milk.